1. Field of the Invention
The present invention relates to a moving object position display device and method which detect the current position of a moving object to read road map data corresponding to the moving object position and display a moving object mark on the road map displayed on the display to guide a route.
2. Description of the Related Art
A vehicle navigation device is given as an example of a moving object position display device. The related art navigation device detects the current position of a user's vehicle as a moving object by current position detection means such as a GPS (Global Positioning System) receiver. The navigation device reads road map data corresponding to the current position from a storage medium such as a DVD (Digital Versatile Disc)-ROM to display the map on the display. The navigation device searches for a recommended route to a destination set by the user using route search means. The navigation device displays the recommended route overlapped with the map on the display with a user's vehicle mark, thereby guiding the user to the destination. When the user's vehicle position makes an approach to a junction such as an intersection and an interchange, its enlarged view and three-dimensional view are displayed to guide a driving direction and a distance to a reaching point by voice. Road traffic information such as traffic jam information on a route is obtained from a road beacon or FM multiplex broadcasting in VICS (Vehicle Information and Communication Systems) to be displayed on the display.
A user's vehicle mark displayed on the map on the display is very important for indicating the current position of a user's vehicle. The displayed position of the user's vehicle mark is determined by map matching of the detected result of the current position detection means with the road map data. When there is a problem in the detection accuracy of the current position detection means, the user's vehicle mark will be displayed to be off the road or displayed on a different road. There has been proposed a navigation device which judges the position state of a user's vehicle mark and changes the display form of a display object (such as a facility, river, and one-way road) in which the user's vehicle mark on a map display screen is positioned so that the user can easily recognize the current state (see Japanese Patent Application Publication No. 2002-340590). An attempt to provide additional information to a user's vehicle mark itself has been made. There has been known a driving guiding device which changes the color of a user's vehicle mark in the case of detecting a user's vehicle position by radio navigation using a GPS receiver and of detecting a user's vehicle position by autonomous navigation using a direction sensor and a speed sensor (see Japanese Patent Application Publication No. Hei 03-131714).
The related art navigation device cannot be sufficient although an attempt to provide additional information to a user's vehicle mark itself has been made. In driving using the navigation device, a driving route from the current position to a destination is displayed. When searching for a facility such as a restaurant during driving, the user needs to stop the vehicle once to check it. A lot of location information or landmark information on the facility is displayed on the map screen displayed on the display. It is not preferable to search for it while driving.